Ice swimming and changes in body core temperature: a case study.

Beat Knechtle,Christoph A Rüst,Thomas Rosemann

doi:10.1186/s40064-015-1197-y

Abstract

Introduction‘Ice Mile’ swimming is a new discipline in open-water swimming introduced in 2009. This case study investigated changes in body core temperature during preparation for and completion of two official ‘Ice Miles’, defined as swimming 1.609 km in water of 5°C or colder, in one swimmer.Case descriptionOne experienced ice swimmer (56 years old, 110.2 kg body mass, 1.76 m body height, BMI of 35.6 kg/m2, 44.8% body fat) recorded data including time, distance and body core temperature from 65 training units and two ‘Ice Miles’.Discussion and evaluationDuring training and the ‘Ice Miles’, body core temperature was measured using a thermoelectric probe before, during and after swimming. During trainings and the ‘Ice Miles’, body core temperature increased after start, dropped during swimming but was lowest during recovery. During training, body core temperature at start was the only predictor (ß = −0.233, p = 0.025) for the increase in body core temperature. Water temperature (ß = 0.07, p = 0.006) and body core temperature at start (ß = −0.90, p = 0.006) explained 61% of the variance for the non-significant decrease in body core temperature. Water temperature (ß = 0.077, p = 0.0059) and body core temperature at finish (ß = 0.444, p = 0.02) were the most important predictors for the lowest body core temperature. In ‘Ice Miles’, body core temperature was highest ~6–18 min after the start (38.3–38.4°C), dropped during swimming by 1.7°C to ~36.5°C and was lowest ~40–56 min after finish. The lowest body core temperature (34.5–35.0°C) was achieved ~100 min after start.ConclusionsIn an experienced ice swimmer with a high BMI (>35 kg/m2) and a high percent body fat (~45%), body core temperature decreased by 1.7°C while swimming and by 3.2–3.7°C after the swim to reach the lowest temperature in an official ‘Ice Mile’. The swimmer suffered no hypothermia during ice swimming, but body core temperature dropped to <36°C after ice swimming. Future athletes intending to swim an ‘Ice Mile’ should be aware that a large body fat prevents from suffering hypothermia during ice swimming, but not after ice swimming.

Highlights

Open-water swimming is of high popularity (Eichenberger et al 2012)
In an experienced ice swimmer with a high BMI (>35 kg/m2) and a high percent body fat (~45%), body core temperature decreased by 1.7°C while swimming and by 3.2–3.7°C after the swim to reach the lowest temperature in an official ‘Ice Mile’
The swimmer suffered no hypothermia during ice swimming, but body core temperature dropped to

Summary

Introduction

Open-water swimming is of high popularity (Eichenberger et al 2012). Apart from the ‘English Channel Swim’ held since 1875 (Knechtle et al 2014), competitive open-water ultra-distance swimming is held at world class level since 2000 for different distances such as 5, 10 and 25 km (Vogt et al 2013; Zingg et al 2014).Knechtle et al SpringerPlus (2015) 4:394A very young and new discipline in open-water swimming is the so-called ‘ice mile swimming’. Open-water swimming is of high popularity (Eichenberger et al 2012). Apart from the ‘English Channel Swim’ held since 1875 (Knechtle et al 2014), competitive open-water ultra-distance swimming is held at world class level since 2000 for different distances such as 5, 10 and 25 km (Vogt et al 2013; Zingg et al 2014). A very young and new discipline in open-water swimming is the so-called ‘ice mile swimming’. The IISA introduced the ‘Ice Mile’ as its ultimate achievement of swimming in ice cold water where an ‘Ice Mile’ is defined as swimming one mile (1.609 km) in water of 5°C or colder. In addition to the ‘Ice Mile’, the IISA introduced in 2014 the ‘1 km Ice event’. Since 2009 and 2014, swim times in ‘Ice Mile’ and ‘1 km Ice event’, respectively, are recorded

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